It is becoming increasingly apparent that communication systems involving fixed client terminals and server units are no longer the only pervasive means of communication available to large segments of society. In particular, certain current and next-generation client devices are no longer tied to use at a single physical location or limited to a single application. Such portable client terminals are predicted to emerge as ubiquitous communication and computing platforms, capable of enabling the convergence of consumer electronics, computing, and communications. In order for this type of convergence to fulfill its promise, client terminals will need to become capable of accessing a multiplicity of applications and services while seamlessly connecting to a variety of wireless access networks.
Such convergence may be evaluated from at least two perspectives. First, the manner in which multiple wireless networks may be configured to facilitate such convergence needs to be considered. This will enable the creation of user scenarios aiding in the development of mobile terminal architectures designed to interoperate with such multiple networks. Secondly, convergence from the perspective of end-users should be understood in order that any proposed system solutions accommodate the needs of such end-users to the greatest extent possible given applicable network constraints.
From a network perspective, efforts are being made to achieve such convergence through integration of wireless local area networks (“WLANs”) and third-generation (“3G”) cellular systems developed in accordance with the Universal Mobile Telecommunications System (UMTS). Such 3G cellular systems include, for example, integrated systems based upon Global System Mobile (GSM) and General Packet Radio Service (GPRS) (i.e., GSM/GPRS systems), as well as wideband code division multiple access systems (WCDMA). Varying degrees of integration of a 3G cellular system and a WLAN may be achieved. For example, a certain degree of integration may be obtained merely through sharing of billing and subscriber profile information. On the other hand, a relatively greater degree of integration may be achieved through integration of the core network functionality of the WLAN and the 3G cellular system. Although the latter approach promises to yield a more complete set of network functions, it would constitute an extremely complicated and expensive undertaking. Furthermore, in view of the evolving nature of both the WLAN and UMTS standards, near term prospects of comprehensive integration of WLAN and 3G cellular systems seem rather dim. Accordingly, it is probable that the former type of integration and coordination among systems will likely be the only approach to be implemented within the foreseeable future.
Turning now to FIG. 1, an illustrative representation is provided of an exemplary wireless communication system 100 within which the former type of integration may be attained by connecting the billing and subscriber profiles for a WLAN 104 and a UMTS network 106. As may be appreciated from FIG. 1, the WLAN 104 and UMTS network 106 share a common authentication system 110 and a common billing system 114.
The UMTS network 106 is comprised of several primary portions including a mobile subscriber terminal 118 and associated Subscriber Identity Module (SIM) 120, a UMTS radio network 124, and a UMTS core network 126 containing switching infrastructure and network intelligence. During operation of the system 100, the subscriber terminal 118 communicates with base stations within the UMTS radio network 124. Such base stations convert radio signals from the subscriber terminal 118 into digital signals which are provided to the switching infrastructure within the UMTS core network 126. This switching infrastructure establishes call connections with other subscriber terminals, or routes the digital signal information to the public switched telephone network (PSTN) or other data network (e.g., the public packet data network (PPDN) or the Internet).
The SIM 120 is realized as an electronic card and provides subscriber identity information to the subscriber terminal 118, which transmits this information to the UMTS radio network 124 in order to gain access to the UMTS core network 126. The UMTS core network 126 then verifies the validity of the subscriber identification information before authorizing access to the subscriber terminal 118. Within the UMTS network 106, the SIM 120 is used as the primary subscriber identification and encryption mechanism, although this capability has not been standardized within WLAN environments. However, several approaches have been proposed for development of authentication and encryption solutions for deployment within WLANs using SIM/USIM technology.
It is anticipated that SIM/USIM technology will play a key role in enabling the convergence of WLAN and cellular systems at a network level by enabling joint authentication (and by implication also billing). It is further believed that this technology may play a key role in solving many of the security issues that have hindered deployment of WLAN systems.
From an end-user perspective, the promise of third generation wireless systems has always been the delivery of a diverse range of services to anyone, anywhere, anytime and at the lowest possible cost. During the early stages of the development of UMTS networks, the vision was that the combination of existing GSM/GPRS networks with the newly developed WCDMA networks would fulfill this promise. However, the development and commercialization of WLAN technologies (specifically 802.11a/b) has been gaining momentum. Among many experts, the current consensus seems to be that both systems will co-exist. In this regard it appears that end users will be less concerned with the availability of a particular technology than with the reliable delivery of multiple different types of advanced services. In order to enable such convergence of service offerings, network operators must ensure the availability of subscriber terminals capable of securely executing a number of different applications. In addition, it will also be desired to deliver such advanced services using the lowest-cost network infrastructure available. Accordingly, the architecture of next-generation mobile terminals will ideally be capable of receiving services or applications via a number of different bearer options (e.g. GSM/GPRS, WCDMA, and 802.11a/b).
Turning now to FIG. 2, a block diagram is provided of the baseband platform of a typical second generation (2G) wireless handset 200. As shown, handset 200 typically includes a processor 204 (e.g., an ARM7 or the equivalent) and a 16-bit DSP 208. Firmware of the DSP 208 is typically executed from ROM (not shown), while software executed by the processor 204 is stored in “off-chip” FLASH memory 212. The handset 200 also typically includes a limited amount of off-chip SRAM 216, as well as a SIM interface 220 configured to accept an electronic SIM card of the type described above. With slight modification, the platform 200 may also be used to implement dual-mode GSM/GPRS solutions. Typically, a processor 204 of higher speed (e.g., an ARM9 processor) is used in the GSM/GPRS handset, and the clock speed of the 16-bit DSP 208 is also increased. A higher-speed processor 204 such as the ARM9 is not only capable of running the GSM/GPRS protocol stack, but also of concurrently executing applications.
Accordingly, from an end user perspective a number of the ingredients necessary to support convergence are present within existing handset technology; namely, sufficient processing and computing capability to support a number of different applications and services, and a SIM interface enabling subscriber access to a unified authentication and billing platform. However, existing handsets are generally incapable of supporting multiple radio protocols or “bearers”, thereby limiting the convergence of the different services offered via various bearers. For example, certain existing GSM handsets are capable of accessing and displaying information via Internet web browsing, but are not disposed to seamlessly roam between GSM networks and other types of radio networks such as, for example, WLAN, Bluetooth or 3G WCDMA networks.
Accordingly, it would be desirable to provide for seamless mobility between radio networks operative in accordance with different protocols. In order enable such mobility and the consequent convergence in services, it would also be desirable to provide a mobile wireless terminal that inexpensively supports operation of multiple bearers and services.